LinearLayoutやRecyclerViewの、もともと用意されている区切り線について
LinearLayout
android:divider="?android:dividerHorizontal" android:showDividers="beginning|middle|end"
RecyclerView
final DividerItemDecoration decoration = new DividerItemDecoration(getContext(), DividerItemDecoration.VERTICAL); recyclerView.addItemDecoration(decoration);
もともと用意されているDrawable
android:background="?android:attr/listDivider"